Figure 5

Variability of the Travel-Time Expenditures among cities. (Left) Different behaviours of the empirical hazard functions to model the mobility in a city. Hazard functions \(\lambda (T)\) for the cities of Milan in Northern Italy with 1.3 millions inhabitants (dash line), Rome, the capital, in Central Italy with 2.7 millions inhabitants (solid line), Naples in Southern Italy 1 million inhabitants (dot line) and Palermo in Sicily 700 thousand inhabitants (dot-dash line). We have significant differences, particularly in the height of the plateau (\(1/\beta\)) that is related to the TTB. (Right) Average TTE in Italian cities. The distribution of the average TTE for 1,233 Italian municipalities where we have at least 100 GPS equipped vehicles (dots and lines) can be interpolated with a Gaussian with mean 1.43 h and standard deviation 0.15 h (solid line).